If you were given a few seconds to name a sea creature you wouldn’t want to run into during a swim on the beach there’s a good chance you’d arrive at “a shark.” It’s a good answer and, even if shark attacks are relatively rare, it’s hard not to see a shark’s intimidating grin and see it as anything other than a threat.

With that kind of a reputation you might imagine that sharks have very little to fear in the sea. They’re apex predators that have existed for millions of years, honing their skills to become the ultimate ocean killers. As it turns out, even sharks have something to fear, and a new research effort reveals the one thing that strikes fear in the heart of a white shark: an orca.